Re: SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weirdcrap with vdso on uml/i386)

[Al Viro]

On Sun, Aug 21, 2011 at 09:11:54PM -0700, H. Peter Anvin wrote:
> > lack of point - the *only* CPU where it would matter would be K6-2, IIRC,
> > and (again, IIRC) it had some differences in SYSCALL semantics compared to
> > K7 (which supports SYSENTER as well).  Bugger if I remember what those
> > differences might've been...  Some flag not cleared?
> 
> The most likely reason for a binary to execute a stray SYSCALL is
> because they read it out of the vdso.  Totally daft, but we certainly
> see a lot of stupid things as evidenced by the JIT thread earlier this
> month.

Um...  What, blindly, no matter what surrounds it in there?  What will
happen to the same eager JIT when it steps on SYSENTER?
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